Health officials announced all schools in the Village of New Square, Spring Valley and Monsey keep all unvaccinated or under-vaccinated students home from school until 21 days have passed from the last confirmed measles case, ABC reports.

10 schools have been impacted with cases of measles, according to health officials. A total of 15 schools in Rockland County are impacted by the new restrictions.

Measles is a highly contagious respiratory disease caused by a virus that is spread by direct contact with nasal or throat secretions of infected people. People first develop a fever, then often a cough, runny nose and watery eyes, followed by an appearance of a rash. People are considered infectious four days before to four days after the appearance of the rash.

Symptoms include a fever, rash, cough, conjunctivitis or a runny nose. Symptoms usually appear 10-12 days after exposure but may appear as early as 7 days and as late as 21 days after exposure.